As founder of cloudHQ, I have to jump into this. Software products will have bugs. And people will make mistakes. We are all human.

So even if you store data in Dropbox - it is smart to have one extra copy in some other cloud storage. Like Google Drive. Or Box. Or Egnyte. So if data is deleted in Dropbox (accidentally, maliciously, or due to a bug) you can restore it from other cloud.

Of course, cloudHQ is the system which can do that: http://chq.io/hnsc